Methods and compositions for prophylactic and therapeutic treatment of infections

ABSTRACT

A new class of soluble phosphorylated glucans is described as well as the process for making the same. According to one embodiment, the soluble phosphorylated glucan is derived from the yeast Saccharomyces cerevisiae. The soluble phosphorylated glucans are useful for prophylactic and therapeutic applications against neoplastic, bacteria, viral, fungal and parasitic diseases. The soluble phosphorylated glucans are used either alone or in combination with a known antimicrobial agent for prophylactic and therapeutic antimicrobial applications. Additionally, they may be administered as a non-toxic adjuvant, in combination with chemotherapy. The soluble phosphorylated glucans are also useful for stimulating macrophage cells, either in vivo or in vitro, to produce a cytotoxic/cyctostatic factor effective against cancer cells.

CROSS-REFERENCE TO RELATED APPLICATION

This is a division of application Ser. No. 013,082, filed Feb. 10, 1987, now U.S. Pat. No. 4,761,402 and a continuation-in-part of copending Ser. No. 767,388, filed on Aug. 19, 1985, now U.S. Pat. No. 4,739,046.

TABLE OF CONTENTS

1. Field of the Invention

2. Background of the Invention

2.Immunobiological Activity of Particulate Glucans

2.2. Adverse Side Effects of Particulate Glucans

2.3. Unsuccessful Attempts to Solubilize Particulate Glucans

3. Summary of the Invention

4. Brief Description of the Figures

5. Detailed Description of the Invention

5.1. Process for Preparation of Soluble Phosphorylated Glucan

5.2. Characterization of Soluble Phosphorylated Glucan

5.2.1. Elemental Composition

5.2.2. Structural Configuration

5.2.2.1. Molecular Sieving

5.2.2.2. Nuclear Magnetic Resonance Spectroscopy

5.3. Non-toxicity, Non-pyrogenicity and Non-Immunogenicity of Soluble Phosphorylated Glucan

5.3.1. Non-Toxicity

5.3.2. Non-Pyrogenicity

5.3.3. Non-Immunogenicity

5.4. Prophylaxis and Therapy of Infectious Diseases

5.5. Routes and Methods of Administration

6. Preparation of Soluble Phosphorylated Glucans

6.1. Preparation from Particulate Glucan Obtained from Saccharomyces

6.2. Preparation from Coriolus versicolor

6.3. Preparation from Sclerotium

7. Immunobiological Properties of Soluble Phosphorylated Glucans

7.1. Modification of Enhanced Susceptibility to Opportunistic Infections in Immuno-Suppressed Animals

7.1.1. Enhanced Survival

7 1.2. Enhanced Resistance of Immuno-Suppressed Mice to Escherichia coli Infection

7.2. Modification of Bacterial Diseases in Animals By In Vivo Administration of Soluble Phosphorylated Glucan

7.2.1. Modification of Staphylococcus aureus Induced Sepsis

7.2.2. Modification of Escherichia coli - Induced Peritonitis

7.2.2.1. Time Required for Protective Effect

7.2.2.2. Dose-Response

7.2.2.3. Effectiveness of Soluble Phosphorylated Glucans

7.3. Effect of Soluble Phosphorylated Glucan on Viral-Induced Hepatitis

7.4. Effect of Orally Administered Soluble Phosphorylated Glucan on Candida albicans Induced Sepsis

7.5. Enhancement of Macrophage Phagocytic Activity

7.6. Enhancement of Macrophage Secretory Activity

8. Synergistic Effect of Soluble Phosphorylated Glucan and an Antibiotic Against E. coli Induced Infection

1. FIELD OF THE INVENTION

This invention relates to pharmaceutical compositions and methods for prophylaxis and therapeutic treatment of infections. More particularly, the invention relates to compositions and methods for prophylactic and therapeutic treatment of infectious diseases induced by a variety of microorganisms utilizing a novel class of soluble phosphorylated glucans in which the poly-[beta-(1-3) glucopyranose] chains are phosphorylated in varying degrees.

2. BACKGROUND OF THE INVENTION

The term "glucan" refers generically to a variety of naturally occurring homopolysaccharides or polyglucoses, including polymers such as cellulose, amylose, glycogen, laminarians, starch, etc. Glucan encompasses branched and unbranched chains of glucose units linked by 1-3, 1-4, and 1-6 glucosidic bonds that may be of either the alpha or beta type.

As defined herein, "particulate glucan" designates a water-insoluble particulate (about 1-3 microns) polyglucose such as that derived from the cell wall of the yeast Saccharomyces cerevisiae. Particulate glucan is macromolecular and comprises a closed chain of glucopyranose units united by a series of beta-1-3 glucosidic linkages. (Hassid et al., 1941, J. Amer. Chem. Soc. 63: 295-298; Di Luzio et al., 1979, Int'l J. Cancer 24: 773-779). X-ray diffraction studies have demonstrated that particulate glucans exist in the form of triple-stranded helices. (Sarko et al., 1983, Biochem. Soc. Trans. 11: 139-142).

2.1 IMMUNOBIOLOGICAL ACTIVITY OF PARTICULATE GLUCANS

Particulate glucan is a potent activator of the macrophage/monocyte cell series, complement, as well as of B cell lymphocytes. Thus, particulate glucan has profound effects on both the reticuloendothelial and immune systems.

Previous studies have demonstrated that in vivo administration of particulate glucan to a variety of experimental animals induces a number of profound immunobiological responses, including the following: (1) enhanced proliferation of monocytes and macrophages (Deimann and Fahimi, 1979, J. Exper. Med. 149:883-897; Ashworth et al., 1963, Exper. Molec. Pathol., Supp. 1:83-103); (2) enhanced macrophage phagocytic function (Riggi and Di Luzio, 1961, Am. J. Physiol. 200: 297-300); (3) enhanced macrophage secretory activity (Barlin et al., 1981, in Heterogeneity of Mononuclear Phagocytes, Forster and Landy, eds., Academic Press, New York, pp. 243-252); (4) increased macrophage size (Patchen and Lotzova, 1980, Exper. Hematol. 8: 409-422); (5) enhanced macrophage adherence and chemotactic activity (Niskanen et al., 1978, Cancer Res. 38: 1406-1409); and (6) enhanced complement activation (Glovsky et al., 1983, J. Reticuloendothel. Soc. 33: 401-413). Increased cytolytic activity against tumor cells has been demonstrated in macrophages from animals and man treated with particulate glucan in both in vivo (Mansell and Di Luzio, 1976, in "The Macrophage in Neoplasia", Fink, ed., Academic Press, New York, pp. 227-243) and in vitro studies [Schultz et al., in Immune Modulation and Control of Neoplasia by Adjuvant Therapy, M. A. Chirigos, ed. Raven Press, New York, pp.241-48 (1978)].

Stimulation of the reticuloendothelial system by in vivo administration of particulate glucan leads to inhibition of allogenic or xenogenic bone marrow graft acceptance in lethally irradiated animals. (See, e.g. Wooles and Di Luzio, 1964, Proc. Soc. Exper. Biol. Med. 115: 756-759). This finding denotes that glucan will induce host defense mechanisms even against normal cells if they are genetically different from the host.

In addition to effects on reticuloendothelial and immune responses, in vivo administration of particulate glucan has been demonstrated to enhance hemopoietic activity including granulopoiesis, monocytopoiesis and erythropoiesis leading to greater recovery from a lethal dose of whole body irradiation (Patchen, 1983, Surv. Immunol. Res. 2: 237-242).

A number of studies have indicated that in vivo administration of particulate glucan significantly modifies host resistance to a wide variety of infectious diseases induced by bacterial, fungal, viral and parasitic organisms. In particular, enhanced host resistance to infection has been shown when animals are challenged by microorganisms such as Eshericheria coli, Staphylococcus aureus, Francisella tularensis, Mycobacterium leprae, Streptococcus pneumoniae, Candida albicans, Sporotrichum schenckii, as well as viruses such as Venezuelan equine encephalomyelitis virus, Rift Valley fever virus, murine hepatitis virus, frog virus III, Herpes simplex I and II, and parasites such as Leishmania donovani (see review by Di Luzio, 1983, Trends in Pharmacol. Sci. 4: 344-347 and references cited therein).

Extensive studies have indicated that particulate glucan has potent anti-tumor activity. For example, particulate glucan has been shown to inhibit tumor growth and prolong survival in four syngeneic murine tumor models including adenocarcinoma BW 10232, anaplastic carcinoma 15091A, melanoma B16, and spontaneous lymphocytic leukemia BW5147 (Di Luzio et al, 1979, in Advances in Experimental Medicine and Biology, Vol. 121A: 269-290).

To evaluate the cellular basis of the anti-tumor activity of particulate glucan, the anti-tumor cytotoxic activity of peritoneal macrophages, derived from control and particulate glucan-treated mice, was studied (Mansell and Di Luzio, 1976, in The Macrophage in Neoplasia, Fink, ed. Academic Press, New York, pp. 227-243). These studies indicated that peritoneal macrophages from glucan-treated mice produced a significant cytotoxic response compared to normal macrophages. This observation has been confirmed (See, e.g., Barlin et al. 1981, in Heterogenity of Mononuclear Phagocytes, Forster and Landy, eds., Academic Press, New York, pp. 243-252) and Chirigos et al., 1978, Cancer Res. 38: 1085-1091).

Additionally in vitro studies using normal and tumor cells incubated with particulate glucan have demonstrated that glucan exerts a direct cytostatic effect on sarcoma and melanoma cells and a proliferative effect on normal spleen and bone marrow cells (Williams et al., 1985, Hepatology, 5: 198-206). These studies indicate that glucan, when administered therapeutically, will (1) significantly inhibit hepatic metastases; (2) inhibit the growth of the primary tumor; and (3) enhance survival, possibly by increased Kupffer cell tumoricidal activity as well as by a direct cytostatic effect of such glucan on sarcoma cells.

Notwithstanding these biological properties, the adverse side effects of particulate glucans have made these compounds all but useless in clinical medicine.

2.2. ADVERSE SIDE EFFECTS OF PARTICULATE GLUCANS

When particulate glucan is administered in vivo to animals, a number of severe side effects have become apparent, the most notable being:

(1) formation of granuloma;

(2) development of hepatosplenomegaly;

(3) increased susceptibility to endotoxins;

(4) activation of complement (anaphylyotoxin);

(5) development of pulmonary granulomatous vasculitis;

(6) development of hypotension following intravenous administration; and

(7) development of microembolism when administered at high concentrations.

Additionally, there is a relatively high degree of acute toxicity observed when particulate glucan is administered in vivo. For example, following a single intravenous injection of an aqueous suspension of particulate glucan, 20% and 100% morality were observed in mice receiving glucan at 250 and 500 mg/kg body weight respectively.

Moreover, due to the particulate nature of the glucan preparation (1-3 microns), it is difficult to administer via an intravenous route. By way of illustration, one patient receiving particulate glucan required constant supervision during intravenous (IV) administration, continuous shaking of the IV drip bottle being essential to maintain the particulate glucan in suspension to avoid formation of emboli in the patient.

Although slightly soluble neutral glucans are commerically available, these preparations are not suitable for intravenous administration because the aqueous solutions have very high viscosity and, more importantly, because their use when administered to experimental animals has inevitably been accompanied by considerable toxicity.

Lentinan, a high molecular weight and poorly soluble beta-1,3 and beta-1,6 glucan obtained from Lentinus edodes, has been studied following intravenous administration to dogs. A variety of adverse clinical effects were observed following adminstration of lentinan (Ajinomoto Co. Inc., Tokyo, Japan) at doses of 2.0, 8.0 and 30 mg/kg/day for 5 weeks. Adverse effects included vomiting, erythema, discoloration of the sclera, and facial swelling. Circulatory collapse, unsteady gait, altered behavioral patterns, excessive salivation were also seen in individual beagles. At autopsy, congestion of the gastrointestinal mucosa was observed in animals treated with 2.0 or 8.0 mg/kg/day. Morphological changes of liver indicated intracytoplasmic material, possibly lentinan, accumulating in liver cells. One animal showed circulatory collapse upon the first injection at 8.0 mg/kg. While he did recover, the animal experienced repeated vomiting episodes with presence of blood indicating hemorrhaging of the gastrointestinal tract. Another animal appeared to show a marked allergic response, as demonstrated by erythema and subcutaneous swelling (edema) of the face. Autopsy findings demonstrated extensive edema of subcutaneous tissue, and congestion of the gastrointestinal tract with hemorrhaging. Macrophage cells showed accumulation of material, possibly lentinan. (Chesterman et al., 1981, Toxicol. Lett. 9:87-90)

Additional toxicity studies were performed in which a variety of doses of lentinan ranging from 0.1 to 1.0 mg/kg/day were given intravenously to rats for 9 weeks. Toxicity was manifested by the development of cutaneous lesions and discoloration of the ears suggesting thromboembolic events. (Cozens et al., 1981, Toxicol. Lett. 9:55-64).

2.3. UNSUCCESSFUL ATTEMPTS TO SOLUBILIZE PARTICULATE GLUCANS

In view of these disadvantages of particulate beta-1,3 glucans for in vivo administration, extensive studies were undertaken to develop a soluble beta-1,3 polyglucose which might be non toxic, induce no significant pathology, and yet retain significant immunobiological activity.

A low molecular weight non-phosphorylated soluble glucan preparation prepared by formic acid hydroylsis of particulate glucan has been shown to have anti-tumor and anti-staphylococcal activity (Di Luzio et al., 1979, Internat'l J. Cancer 24: 773-779). Unfortunately, the low yield and diversity of fractions obtained by this method made this preparation non-useful for prophylactic and therapeutic applications. (see Di Luzio, 1983, Trends in Pharmacological Sciences 4: 344-347).

Similarly, attempts to solubilize particulate glucan by the addition of dimethylsulfoxide (DMSO) a "molecular relaxant" were also unsuccessful. It was thought the DMSO would "relax" the triple helical configuration of the glucan molecule. However, particulate glucan did not dissolve in the presence of DMSO. All attempts to isolate a soluble glucan from the DMSO solution resulted in failure. Upon dilution of the DMSO-glucan solution with various aqueous media such as glucose or saline solutions, the particulate glucan was reformed. Following dilution of the DMSO-soluble glucan solution with saline, all animals receiving injections of these solutions died immediately upon injection due to high concentration of DMSO or the reformation of the particulate glucan. Upon precipitation of the glucan in DMSO solution by the addition of ethanol (100%), the precipitate was collected and lyophilized. When this lyophilized glucan was added to water, the particulate glucan reformed.

Attempts to convert the neutral glucan preparation of particulate glucan to a polar-charged preparation by the addition of phosphate or sulfate groups as well as by acetylation were also unsuccessful. Each of these procedures was conducted following the attempted solubilization of particulate glucan by DMSO and in each instance the particulate glucan was reformed.

3. SUMMARY OF THE INVENTION

During an exhaustive investigation of methods by which the triple-stranded helices of glucan might be "relaxed" sufficiently to permit reaction of each of the chains, it was found that when particulate glucan was dissolved in a highly polar solvent (such as DMSO) in the presence of a strong chaotropic agent (such as urea), the glucan is sufficiently structurally disrupted to allow phosphorylation of each of the single chains (or strands) such that the resultant phosphorylated glucan shows the substantially complete absence of the characteristic triple helical structure of particulate glucan. Removal of the resultant phosphorylated gluca shows it to be soluble in water, non-toxic, non-immunogenic, substantially non-pyrogenic and capable of exerting profound immunobiological responses when administered in vivo to animals and humans.

Based on these discoveries, the invention provides a new class of soluble phosphorylated glucans (a) in which the poly-[beta-(1-3)glucopryanose] chains are phosphorylated in varying degrees; (b) which are non-toxic, non-immunogenic, substantially non-pyrogenic, and (c) which are capable of exerting pronounced immunobiological responses when administered in vivo in animals and humans. These new soluble phopsphorylated glucans, which are further characterized by a substantial absence of the triple helical structure of particulate glucans, immunostimulate macrophage activity with resulting activation of other immunoactive cells in the reticuloendothelial and immune systems. Additionally these soluble phosphorylated glucans enhance hemopoietic activity including but not limited to leukopoiesis. These soluble phosphorylated glucans exhibit cytostatic effects against adenocarcinomas and sarcomas in vivo, and against lymphocytic leukemia cells in vitro. Not only do these soluble phosphorylated glucans stimulate macrophage cells in vivo, but they exert profound stimulatory effects on macrophage cells cultured in vitro. Such immunostimulation of macrophage cells is invariably accompanied by production of a macrophage cytotoxic/cytostatic factor (MCF), protein or proteins of unknown structure, which are selectively toxic to cancers cells, particularly adenocarcinomas.

Additionally, the invention provides a process for producing these soluble phosphorylated glucans by dissolving a particulate glucan (preferably prepared from Saccharomyces cerevisiae although other microbial sources may be used) in a highly polar solvent which contains a strong chaotropic agent, and reacting the resultant glucan with phosphoric acid to form a soluble phosphorylated glucan, and recovering the resultant phosphorylated glucans from the reaction mixture.

The invention provides compositions and methods for prophylaxis and therapy of infections, induced by a variety of microorganisms including bacteria, fungi, viruses and parasitic organisms, which comprise administering an effective amount of a soluble phosphorylated glucan or a pharmaceutical composition comprising soluble phosphorylated glucan in combination with a physiologically acceptable carrier to an animal or a human. Additionally, compositions and methods are provided for therapy of infections induced by such agents which comprise administering a therapeutically effective amount of a composition comprising a soluble phosphorylated glucan in combination with an antimicrobial agent effective against the infection.

The immunobiological properties of the soluble phosphorylated glucans used in the present invention include (1) the ability to prevent mortality due to overwhelming gram negative bacterial infections; (2) the ability to prevent mortality due to gram positive bacterial infections; (3) the ability to modify mortality from spontaneous infections in profoundly immuno-suppressed animals and man; (4) the ability to modify enhanced susceptibility of immunosuppressed animals and man to gram negative bacterial infections; (5) the ability to significantly modify viral infections; (6) the ability to modify spontaneous infections induced by fungal and other parasitic microorganisms; (7) the ability to act synergistically with anti-microbial agents for the prophylactic and/or therapeutic treatment of infections induced by microorganisms including bacteria, fungi, viruses and parasitic organisms and the like; (8) the ability to significantly inhibit primary tumor growth when used alone and to exert a synergistic effect against primary tumor growth when used in combination with anti-cancer agents; and (9) the ability to act synergistically with anti-cancer agents in the regression of primary malignant lesions as well as metastatic lesions in animals and man.

4. BRIEF DESCRIPTION OF THE FIGURES

The present invention may be more fully understood by reference to the following detailed description of the invention, examples of specific embodiments and the appended figures in which:

FIG. 1 is a representation of the nuclear magnetic resonance spectrum of soluble phosphorylated glucan at 27 mg/ml.

FIG. 2 is representation of the nuclear magnetic resonance spectrum of a commercially available preparation of lentinan (Ajinomoto Co. Inc., Tokyo, Japan). FIG. 2A is an illustration of the spectrum obtained at a concentration of 40 mg/ml. FIG. 2B is an illustration of the spectrum obtained at a concentration of 3 mg/ml lentinan.

FIG. 3 is a graph illustrating the effect on survival of corticosteroid-immunosuppressed mice receiving twice weekly injections of soluble phosphorylated glucan. FIG. 3 also illustrates the effect of chronic administration of soluble phosphorylated glucan on survival of normal mice.

FIG. 4 is a graph illustrating the effect of prior in vivo administration of soluble phosphorylated glucan on resistance of both normal and corticosteroid-immunosuppressed mice to Escherichia coli infection.

FIG. 5 is a graph showing the effect of prior treatment with soluble phosphorylated glucan on the lethal effects of a subsequent experimentally induced Staphylococcus aureus infection.

FIG. 6 is a graph illustrating the effect of prior treatment with soluble phosphorylated glucan on survival of mice with subsequent experimentally induced viral hepatitis.

FIG. 7 is a graph illustrating the effect of prior oral administration of soluble phosphorylated glucan on survival of mice with experimentally induced Candida albicans infection.

FIG. 8 is a graph showing the effect of soluble phosphorylated glucan on Interleukin I production.

5. DETAILED DESCRIPTION OF THE INVENTION

Aqueous soluble phosphorylated glucan is advantageously used for prophylactic and/or therapeutic treatment of infectious diseases induced by a variety of microorganisms. Aqueous soluble phosphorylated glucan represents a novel class of soluble phosphorylated glucans in which poly-[beta-(1-3)glucopyranose] chains are phosphorylated in varying degrees. Soluble phosphorylated glucan shows the substantially complete absence of the characteristic triple helical structure of particulate glucan.

Additionally, the novel soluble phosphorylated glucans are used in combination with a known antimicrobial agent for the treatment of infectious diseases.

Further, the soluble phosphorylated glucan of the present invention provides methods and compositions for treatment of malignant neoplastic disease in animals and humans which comprise administering to an animal or a human a therapeutically effective amount of a soluble phosphorylated glucan alone or in combination with an anti-cancer or anti-tumor agent. The invention also provides methods and compositions for prevention of leukopenia induced by administration of an anti-cancer agent which comprise administering to an animal or a human, an effective amount of soluble phosphorylated glucan in combination with said anti-cancer agent.

Furthermore, the invention provides methods for stimulating animal and human macrophage cells (in vivo or in vitro) to produce and secrete a soluble cytotoxic/cytostatic factor (MCF) and the product so produced. Specifically, MCF is produced by administering to an animal or a human a soluble phosphorylated glucan or by culturing animal or human macrophage cells in vitro in culture medium containing soluble phosphorylated glucan. Copending application of Williams, Browder and DiLuzio, Ser. No. 013,298, now U.S. Pat. No. 4,818,752, filed on even date herewith is directed specifically to compositions and methods for these applications and is incorporated herein by reference.

5.1. PROCESS FOR PREPARATION OF SOLUBLE PHOSPHORYLATED GLUCAN

Aqueous soluble phosphorylated glucan is prepared by a process which results in a unique class of products different from any other glucans previously described.

Soluble phosphorylated glucan is prepared from particulate glucan, a neutral polyglucose derived, for example from Saccharomyces cerevisiae, as follows: particulate glucan is suspended in a solution of a strong chaotropic agent in an aprotic solvent such as dimethylsulfoxide (DMSO) with constant stirring. The strong chaotropic agent "relaxes" hydrogen bonding along the polyglucose chain, thus unfolding the molecule. It is preferred to use a fairly high concentration of a strong chaotropic agent such as urea ranging from about 4-12M to prevent reformation of hydrogen bonds. The mixture is then heated and maintained at about 50°-150° C. and phosphoric acid is slowly added with constant stirring. A precipitate comprising the soluble phosphorylated glucan product is apparent after about 1 hour. It is preferred to maintain the reaction mixture at about 100° C. for about 3-12 hours to increase the yield of bioactive product. In practice, after reaction for about 6 hours at about 100° C., the yield is approximately 70-90%. The degree of phosphorylation of the soluble product varies slightly with reaction time (e.g., 1.48% for 3 hours; 2.23% for 6 hours).

The bioactive soluble phosphorylated glucan product is isolated from the reaction mixture as follows: the mixture is cooled to stop the phosphorylation reaction and diluted with a volume of distilled water sufficient to resuspend the precipitate. The resulting solution is filtered through coarse, medium and fine sintered funnels to remove any remaining precipitate. The solution is then molecularly sieved to remove all components of less than about 10,000 daltons molecular weight (MW). Thus, DMSO, urea, glucose and any unreacted phosphoric acid are removed from the solution. Molecular sieving may be accomplished by any method that removes these low (i.e., less than about 10,000 daltons) MW components. In one illustrative example, the solution is sieved using Spectrapor membrane dialysis tubing and dialyzing against running distilled water for about 5 days. In another illustrative example, the solution is sieved using a Millipore dialyzer/concentrator with a 10,000 dalton MW membrane filter and a large volume of dialyzing solution. Following molecular sieving, the resulting solution is concentrated and lyophilized to yield the final soluble phosphorylated glucan in the form of a fluffy powder composition. Crystalline structures are not observed.

The particulate glucan used in the process for preparing the soluble phosphorylated glucan according to the present invention may be isolated from the cell wall of S. cerevisiae by known methods (see e.g , Di Luzio et al., 1979, Internat'l J. Cancer 24: 773-779; Hassid et al., 1941, J. Amer. Chem. Soc. 63: 295-298 incorporated herein by reference). Briefly, in practice the particulate glucan is prepared as follows: dry yeast is digested in aqueous sodium hydroxide solution and heated to about 100° C. for about 4 hours, then allowed to settle overnight. The supernatant is decanted and the procedure is repeated three times. The residue is acidified using hydrochloric acid, heated to and maintained at 100° C. for about 4 hours, and cooled overnight. The supernatant is decanted and the acid digestion is repeated twice. The residue is then washed repeatedly with distilled water and extracted with ethanol for at least 24 hours. The reddish-brown supernatant is then aspirated and discarded. The ethanol extraction is repeated until the supernatant is essentially colorless. The ethanol is removed by repeatedly washing the residue with distilled water. The particulate glucan is collected by centrifugation or filtration.

A variety of compounds, other than urea, known to function as "molecular relaxants" were also evaluated to prevent reformation of hydrogen bonds after DMSO had been used to "relax" the triple helical configuration of particulate glucan. These include (1) ethylene diamene tetracetic acid; (2) hydrazine sulfate; (3) monoethanol amine; (4) guanidine; (5) guanine, and (6) thiourea. Additionally, surfactants and emulsifying agents such as Tween-20 and phospholipid emulsifying agents such as Alcolec and Centrolex f (lecithin) were also employed in an attempt to solubilize and phoshorylate particulate glucan. In no case was a soluble immunobiologically active preparation obtained.

Additionally, soluble phosphorylated glucan can be prepared from neutral polyglucose or polyglucose-protein products derived from a variety of other microbial sources. A non-exhaustive list of such sources is presented in Table 1.

                  TABLE 1                                                          ______________________________________                                         EXAMPLES OF SOURCES OF GLUCAN WHICH CAN BE                                     EMPLOYED FOR THE PREPARATION OF SOLUBLE                                        PHOSPHORYLATED GLUCAN                                                          ______________________________________                                                  Alcaligenes faecalis                                                           Auricularia auricula-judae                                                     Auricularia polytricha                                                         Candida utilis                                                                 Cladosporium fulvum                                                            Claviceps purpurea                                                             Cochiliobolus sativus                                                          Coriolus versicolor                                                            Corlinellus shiitake                                                           Corticium vagum                                                                Grifola umbellata                                                              Lentinus edodes                                                                Pichia fermentans                                                              Poria cocos                                                                    Saccharomyces cerevisiae                                                       Sclerotium coffeicolum                                                         Sclerotium delphnii                                                            Sclerotium glucanium                                                           Sclerotium rolsfi                                                              Shizophyllum commune                                                           Streptococcus salvarius                                                        Stereum sanguinolentum                                                         Wingea robertsii                                                      ______________________________________                                    

According to another alternate embodiment of the present invention, the soluble phosphorylated glucan may be obtained from the medium used to culture an organism such as Sclerotium glucanium using a novel, rapid process. Briefly in practice, a colloidal glucan is prepared from Sclerotium glucanium as follows: a crude sclero-glucan, comprising a polyglucose chain of linearly arranged glucose units linked by beta 1-3 glucosidic bonds in which about 30-35% of the linear chains have a single glucose unit attached via a beta 1-6 bond obtained from the medium used to culture Sclerotium glucanium, is mixed slowly with aqueous sodium hydroxide solution with heat and constant stirring. The mixture is allowed to stand at room temperature for about 4 days, heated to about 50°-100° C. for about 15-60 minutes and then the mixture is allowed to cool to room temperature. The colloidal glucan is isolated from the mixture either by centrifugation or filtration. To illustrate, when filtration is used a series of filters of decreasing pore size such as 3.0, 1.2, 0.8, 0.65 microns are used. The resulting dark amber filtrate is diluted with water and molecularly sieved to removed all components of less than about 10,000 daltons molecular weight. In one illustrative example, the mixture is sieved using spectropor membrane dialysis tubing and dialyzing against 40 liters of water. The final concentrated mixture having about neutral pH is lyophilized yielding an amber spongy glucan material. In another illustrative example, the mixture is dialyzed and concentrated using a Pellicon dialyzing unit. The mixture is dialyzed against 75 liters of pure water. The final concentrated mixture having about neutral pH is lyophilized yielding an amber spongy colloidal glucan material. Soluble phosphorylated glucan is prepared from the colloidal glucan as described above. Briefly, colloidal glucan is suspended in a solution of a strong chaotropic agent in an aprotic solvent such as dimethylsulfoxide (DMSO) with constant stirring. The strong chaotropic agent "relaxes" hydrogen bonding along the polyglucose chain, thus unfolding the molecule. It is preferred to use a fairly high concentration of a strong chaotropic agent such as urea ranging from about 4-12M to prevent reformation of hydrogen bonds. The mixture is then heated and maintained at about 50°-150° C. and phosphoric acid is slowly added with constant stirring. A precipitate comprising the soluble phosphorylated glucan product is apparent after about 1 hour. It is preferred to maintain the reaction mixture at about 100° C. for about 3-2 hours to increase the yield of bioactive product. In practice, after reaction for about 6 hours at about 100° C., the yield is approximately 70-90%. The degree of phosphorylation of the soluble product varies slightly with reaction time (e.g., 1.48% for 3 hours; 2.23% for 6 hours).

5.2. CHARACTERIZATION OF SOLUBLE PHOSPHORYLATED GLUCAN

The solubility of the soluble phosphorylated glucan obtained from S. cerevisiae prepared according to the present invention is greater than about 50 mg/ml in water. Aqueous solutions of the soluble phosphorylated glucan are non-viscous and do not taste sweet.

5.2.1. ELEMENTAL COMPOSITION

The elemental composition of the soluble glucan preparation, determined by Galbraith Laboratories, (Knoxville, TN) is illustrated in Table 2. The data presented in Table 2 permits the average empirical formula of this preparation to be written as follows:

    C.sub.40 H.sub.87 PO.sub.37.

Thus, there is an average of one phosphate group for every 6.6 glucose residues in the soluble phosphorylated glucan.

                  TABLE 2                                                          ______________________________________                                         ELEMENTAL COMPOSITION OF SOLUBLE                                               PHOSPHORYLATED GLUCAN.sup.a                                                    ______________________________________                                         Element or Component                                                                              Mole %                                                      ______________________________________                                         Carbon             34.66                                                       Hydrogen           6.29                                                        Oxygen             42.83                                                       Nitrogen           0.64                                                        Sulfur             0.11                                                        Phosphorus         2.23                                                        Water of Hydration 11.78                                                       ______________________________________                                          .sup.a Determined after 6 hours phosphorylation.                         

5.2.2. STRUCTURAL CONFIGURATION

A number of methods were utilized to determine the molecular weight (MW) and various features of the structural configuration of the soluble phosphorylated glucan.

5.2.2.1. MOLECULAR SIEVING

Column chromatography using Sepharose CL-6B-200 (Pharmacia Fine Chemicals, Piscataway, N.J.) indicated that 80% of the soluble glucan has a MW range from 10,000 to 100,000 daltons, while 20% has a MW range from about 100,000 to about 500,000 daltons.

5 2.2.2. NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY

Carbon-13 nuclear magnetic resonance (¹³ C-NMR) spectroscopy using a Brucker WP-200 spectrometer (Brucker Instruments, Billerica, Mass.) was performed to determine several structural properties of the soluble phosphorylated glucan from S. Cervisiae prepared according to the present invention.

The samples for NMR studies were prepared using a 10% deuterium oxide (D₂ O) in water. Samples were first run with no reference material, and then after the addition of a small aliquot of 1,4-dioxane. All samples were placed in 10 mm diameter tubes.

The ¹³ C-NMR spectral study of soluble phosphorylated glucan indicated a beta-1-3 glucan structure with no branching at the C-6 carbon (see FIG. 1). The NMR spectrum indicates a substantial absence of the triple helical structure of particulate glucans. The degree of phosphorylation was estimated to be 3.6% which is in essential accord with analytical data.

In contrast to the spectra of soluble phosphorylated glucan from S. cerevisiae prepared according to the present invention, a lentinan preparation (Ajinomoto Co. Inc., Tokyo Japan), a branched beta-1-3 and 1-6 D glucan, at either 40 mg/ml (FIG. 2A) or 3 mg/ml (FIG. 2B) demonstrated attenuation of the NMR spectra. This is presumed to be due to the gel state of this molecule, particularly at 40 mg/ml concentration. No signals were obtained in a 10% D₂ O solution in the non-gel 3 mg/ml concentration.

Comparison of FIG. 1 with FIG. 2 demonstrates complete structural and conformational differences between lentinan and soluble phosphorylated glucan. In contrast to the disordered conformation of lentinan at the beta-1-6 linkages (Saito et al., 1977, Carbohydrate Research, 58: 293-305) ordered conformation of soluble phosphorylated glucan according to the present invention is manifested.

5.3. NON-TOXICITY, NON-PYROGENICITY NON-IMMUNOGENICITY OF SOLUBLE PHOSPHORYLATED GLUCAN

Since the soluble phosphorylated glucan offers important advantages over particulate glucan as an injectable biological response modulator, characteristic toxicity, pyrogenicity and immunogenicity of the soluble glucan are described below with particular reference to comparison of these properties of particulate glucan.

5.3.1 NON-TOXICITY

Acute toxicity was evaluated following a single intravenous injection of soluble phosphorylated glucan at a variety of doses into normal animals. Treated animals were observed for 30 days post-injection.

In one series of experiments, 49 ICR/HSD mice were divided into 3 groups of 15 mice each and 2 groups of 2 mice each. Groups 1-3 received 0.5 ml saline solution containing soluble phosphorylated glucan at respectively 40, 200 and 1000 mg/kg; Groups 4 and 5, 1600 and 2000 mg/kg. No mortality was observed in any group. Moreover, no physiological or behaviorial alterations were apparent. In marked contrast, in mice treated similarly with particulate glucan, 20% mortality was observed at 250 mg/kg and 100% mortality at 500 mg/kg.

In another series of experiments, two groups of 5 Sprague Dawley rats each were treated with soluble phosphorylated glucan at respectively 250 and 500 mg/kg via intravenous injection. No mortality or alteration of physiological or behavioral functions was apparent in either group. In contrast, 30% and 100% mortality were observed following intravenous injection of particulate glucan at 75 and 150 mg/kg respectively.

Chronic toxicity was evaluated following twice weekly intravenous injections of saline solution containing soluble phosphorylated glucan at 0, 40, 200 and 1000 mg/kg doses. Body and organ weights, gross and microscopic pathology, serum electrolytes, solutes and serum enzymes indicative of renal and hepatic function were monitored.

In one series of experiments mice were weighed respectively at 0, 8, 11, 15, 22 and 30 days post-treatment with soluble phosphorylated glucan. No significant difference was observed in body weight at any dose of soluble phosphorylated glucan administered. After 30 days chronic treatment, animals were sacrificed. No change was seen in weight of liver, lung and kidney. A statistically significant increase in spleen weight was noted in mice treated with 40 and 100 mg/kg soluble glucan (0.01<p<0.001), but not in mice treated with 200 mg/kg.

In another series of experiments, mice were weighed respectively at 0, 15, 30, 49 and 60 days post-treatment (twice weekly) With soluble phosphorylated glucan. No significant difference was observed in body weight at any dose of soluble phosphorylated glucan administered. After 60 days chronic treatment with soluble phosphorylated glucan, animals were sacrificed. No significant difference was observed in weight of the liver, kidney or lung. A statistically significant increase in spleen weight was apparent in mice treate with 1000 mg/kg soluble phosphorylated glucan (p<0.001).

After 30 or 60 days chronic treatment, no significant alteration was apparent in the following serum components: glucose, blood urea nitrogen (BUN), uric acid, cholesterol, triglycerides, total protein, albumin, globulin, creatinine, calcium, phosphorous, sodium, potassium, chloride, bicarbonate and anion gap. Moreover, no significant alteration was apparent in the following enzymes: alkaline phosphatase, lactic dehydrogenase, serum glutamic oxalacetic transaminase, serum glutamic pyruvic transaminase and creatinine phosphokinase. No change was detectable in serum bilirubin.

Histological studies on tissues obtained from mice following 30 days chronic treatment showed essentially normal liver histology in mice receiving 40 and 200 mg/kg soluble phosphorylated glucan per injection. In animals receiving 1000 mg/kg soluble phosphorylated glucan, monocytic infiltrates were readily apparent in the liver. Lung and kidney tissues were essentially normal in all mice.

Histological studies on tissues obtained from mice following 60 days chronic treatment showed few hepatic granuloma of an isolated nature in animals receiving injections at 40 and 200 mg/kg doses. A higher number of monocytic infiltrates was observed in mice receiving injections at 1000 mg/kg. In all autopsied animals, lung tissue was essentially normal.

Chronic toxicity was further evaluated using guinea pigs (Harlan Sprague Dawley, Houston, Tex.) receiving 5 ml intraperitoneal injections of saline solution containing soluble phosphorylated glucan at 250 mg/kg for 7 days (FDA required test). Results presented in Table 3 indicate that there was an impairment of growth of guinea pigs receiving soluble glucan treatment when compared to controls receiving an equivalent volume of 0.9% saline solution. Following 7 days chronic treatment, body weight of treated animals was, however, significantly increased by 9% as compared to initial weight.

                  TABLE 3                                                          ______________________________________                                         EFFECT OF CHRONIC ADMINISTRATION OF                                            SOLUBLE PHOSPHORYLATED GLUCAN                                                  ON BODY WEIGHT                                                                         Mean Body Weight (gm).sup.a                                            Treat-  Days                                                                   ment    1      2         3    4       5    6       7                           ______________________________________                                         Saline  213.8  225.2     227.4                                                                               234.2   239.7                                                                               244.2   253.8                               ±4.0                                                                               ±6.6   ±7.1                                                                             ±7.3 ±6.1                                                                             ±5.2 ±7.5                     SPGLN.sup.b                                                                            208.9  202.3     203.9                                                                               207.4   214.3                                                                               215.6   227.3*                              ±2.9                                                                               ±5.0   ±5.3                                                                             ±5.3 ±6.0                                                                             ±6.6 ±6.6                     ______________________________________                                          .sup.a Values represent mean body weight (gm) ±standard error. N = 5        animals.                                                                       .sup.b SPGLN designates soluble phosphorylated glucan                          *p < 0.01                                                                

Chronic Toxicity was also evaluated in 2 adult female dogs receiving twice weekly intravenous administration (5 mg/kg) of soluble phosphorylated glucan for 120 days. The dogs were fed Purina Chow and water ad libitum supplemented with one can commercial dog food (Alpo™) twice weekly. Body weight and serum solutes, electrolytes and enzymes were monitored at 0, 17, 24, 38, 80 and 120 days. Following 120 days chronic treatment, a mean weight gain of 2.8 kg or about 22% body weight was observed.

No significant difference was observed in the following serum solutes: glucose, BUN, uric acid, cholesterol, triglycerides, total protein, albumin, globulin, or creatinine. No significant difference was observed in the following serum electrolytes: calcium, phosphorous, sodium, potassium, chloride, bicarbonate, and anion gap. No significant difference was observed in the following serum enzymes: alkaline phosphatase, lactic dehydrogenase, serum glutamic oxalacetic transaminase, serum glutamic pyruvic transaminase and creatinine phosphokinase.

Additonally, no significant difference has been observed in the serum biochemistry of a patient following therapy for 3 months with soluble phosphorylated glucan at 50 mg/ml, administered three times per week.

5.3.2. NON-PYROGENICITY

Pyrogenicity of soluble phosphorylated glucan was evaluated following a single intravenous injection to conscious dogs at doses of 7.5 mg/kg and 30 mg/kg. Body temperature was monitored for 14 days post-injection.

Results presented in Table 4, demonstrate no pyrogenic reaction in this chronic animal model.

                  TABLE 4                                                          ______________________________________                                         ABSENCE OF AN ACUTE OR                                                         CHRONIC PYROGENIC RESPONSE IN DOGS                                                         Mean Body Temperature (°C.)                                 Treatment Dose.sup.a                                                                       Time (Hours)                                                       (mg/kg)     0      1       6    24    144  336                                 ______________________________________                                         7.5         38.3   37.4    38.3 38.3  38.3 38.4                                30.0        38.6   37.0    38.0 38.5  38.4 38.6                                ______________________________________                                          .sup.a N = 3 dogs/group.                                                 

Pyrogenicity was also evaluated using three dogs anesthetized with Nembutal (30 mg/kg) receiving multiple injections of increasing doses of 1, 5, 10, 15, 25 and 50 mg/kg of soluble phosphorylated glucan over a three hour period. Body temperature was determined at 15 minutes following bolus injections. No pyrogenic effect was observed at any dose.

Pyrogenicity of soluble phosphorylated glucan was also evaluated in rabbits. Seven rabbits were divided into 2 groups of 2 and 5 rabbits each. Group 1 received an isovolumetric saline solution; Group 2, received 5 mg/kg soluble phosphorylated glucan in saline solution by intravenous injection. Core body temperature was monitored at 15 minute intervals for 100 minutes following a single bolus injection. Control rabbits showed a mild decrease of 0.2° C. in body temperature. Rabbits treated with soluble phosphorylated glucan showed a mean increase of 0.44° C. Thus, there was a slight pyrogenicity seen in rabbits.

5.3.3. NON IMMUNOGENICITY

The interfacial ring test, designed to detect the presence of IgG antibodies, was used to evaluate the immunogenicity of soluble phosphorylated glucan when chronically administered to dogs for 120 days.

Serum samples were obtained from an adult female dog following 120 days chronic treatment with twice weekly intravenous injections of 5 mg/kg sterile, pyrogen-free soluble phosphorylated glucan. The interfacial ring precipitin test was performed as follows: 0.1 ml of undiluted antisera was pipetted into test tubes. The antigen or phosphorylated soluble glucan at dilutions of 1:2, 1:4, 1:8, 1:16 and 1:32 was layered onto the anti-sera to form a straight interface. Formation of a white precipitin ring at the interface, indicates that presence of antibody specific for the glucan. No precipitin ring was detected at any antigen dilution.

5.4. PROPHYLAXIS AND THERAPY OF INFECTIOUS DISEASES

Due to the potent activity of the soluble phosphorylated glucan in stimulating the immune response and reticuloendothelial system, it is advantageously useful in prophylactic and therapeutic applications against diseases induced by a variety of microorganisms. Because soluble phosphorylated glucan influence very fundamental host defense systems of the body regulating the number, functional activity and interaction of macrophages, T and B lymphocytes, leukocytes and natural killer cells as well as their humoral and secretory components, it possesses the potential for non-specifically modifying an extensive array of infectious diseases.

Soluble phosphorylated glucan demonstrates a number of characteristics which make it particularly advantageous for the treatment of infections including, but not limited to the following advantages:

(1) Soluble phosphorylated glucan has a broad range of activity. It is effective against infections induced by bacteria, fungi, viruses and parasitic organisms;

(2) Soluble phosphorylated glucan does not induce the development of resistance in causative organisms because its effects are mediated by the host;

(3) Soluble phosphorylated glucan has very low toxicity;

(4) Soluble phosphorylated glucan prevents and corrects the development of leukopenia;

(5) Soluble phosphorylated glucan enhances a variety of diverse aspects of cellular and humoral immune responses of the host; and

(6) Soluble phosphorylated glucan prevents or reverses the development of immunosuppression in the host.

The soluble phosphorylated glucan is used to prevent and/or treat diseases induced by gram positive bacteria including, but not limited to: Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae; gram negative bacteria including, but not limited to: Escherichia coli; Bacterium enteritis, Francisella tularensis; acid-fast bacteria including, but not limited to Mycobacterium tuberculosis, and Mycobacterium leprae; viruses including but not limited to: Hepatitis; Herpes simplex I and II; etc.; fungi including, but not limited to: Candida albicans; Sporotrichum schenkii; and protozoal parasites including but not limited to Leishmania donovani, Schistosoma mansoni, etc.

Additionally, the soluble phosphorylated glucan is used for the prevention and treatment of opportunistic infections in animals and man which are immunosuppressed as a result of either congential or acquired immunodeficiency or as a side-effect of chemotherapeutic treatment.

According to an alternate embodiment of the present invention, soluble phosphorylated glucan is used advantageously in combination with a known antimicrobial agent to prevent and/or treat diseases induced by gram positive bacteria including, but not limited to: Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae; gram negative bacteria including, but not limited to: Escherichia coli; Bacterium enteritis, Francisella tularensis; acid-fast bacteria including, but not limited to Mycobacterium tuberculosis, and Mycobacterium leprae; viruses including but not limited to: Hepatitis; Herpes simplex I and II; etc.; fungi including, but not limited to: Candida albicans; Sporotrichum schenkii; and protozoal parasites including but not limited to Leishmania donovani, Schistosoma mansoni, etc.

Moreover, soluble phosphorylated glucan in combination with a known antimicrobial agent is used for the prevention and treatment of opportunistic infections in animals and man which are immunosuppressed as a result of congenital or acquired immunodeficiency or as a side-effect of chemotherapeutic treatment.

Soluble phosphorylated glucan has additive or synergistic effects when used in combination with a broad range of antimicrobial agents effective against diseases induced by bacteria, fungi, viruses and parasitic organisms and the like. Table 5 lists some of the antimicrobial agents that may be used according to the present invention in combination with soluble phosphorylated glucan. Table 5 in no way is meant to be an exhaustive list. Moreover, a combination of one or more antimicrobial agents may be used together with soluble phosphorylated glucan.

                  TABLE 5                                                          ______________________________________                                         EXAMPLES OF ANTIMICROBIAL AGENTS                                               ______________________________________                                         I.        ANTIBACTERIALS                                                                 Aminoglycosides                                                                Streptomycin                                                                   Neomycin                                                                       Kanamycin                                                                      Amikacin                                                                       Gentamicin                                                                     Tobramycin                                                                     Streptomycin B                                                                 Dihydrostreptomycin                                                            Spectinomycin                                                                  Penicillin                                                                     Ampicillin                                                                     Hetacillin                                                                     Amoxicillin                                                                    Carbenicillin                                                                  Cephalosporins                                                                 Cephaloridine                                                                  Cephalothin sodium                                                             Cephaloglycin dihydrate                                                        Cephalexin monohydrate                                                         Tetracycline                                                                   Tetracycline hydrochloride                                                     Oxytetracycline hydrochloride                                                  Chlorotetracycline hydrochloride                                               Doxocycline monohydrate                                                        Methacydine hydrochloride                                                      7-Chloro-6-dimethyltetracycline                                                Erythamycin                                                                    Sulfonamides                                                                   Carbomycin                                                                     Oleanodmycin                                                                   Troleandomycin                                                                 Polymixin B collistin                                                          Chloramphenicol                                                      II.       ANTIFUNGALS                                                                    Amphotericin B                                                                 Flucytosine                                                                    Nystatin                                                                       Grisiofulvin                                                                   Sulfamerizane                                                                  Thimerosal                                                                     Tolnaftate                                                           III.      ANTIVIRALS                                                                     Acyclovir                                                                      3'-azido-3'-deoxythmyidine                                                     Vira A                                                                         Symmetrel                                                                      Idoxuridine                                                                    Bromovinyldeoxuridine                                                          (S)-9-(3-Hydroxy-2 phosphonyl methoxypropyl) adenine                 IV.       ANTIPARASITICS                                                                 Sulfonamides                                                                   Pyrimethamine                                                                  Clindamycin                                                          ______________________________________                                    

Use of a combination of an antimicrobial agent together with soluble phosphorylated glucan is particularly advantageous when the antimicrobial agent has toxic side effects. For example, antibacterial aminoglycosides such as gentamicin, streptomycin, and the like are known to have serious toxicity, particularly ototoxicity and nephrotoxicity, which reduce the usefulness of such antimicrobial agents [see Goodman and Gilman's The Pharmacological Basis of Therapeutics, 6th ed., A. Goodman Gilman et al., eds; Macmillan Publishing Co., Inc., New York, pp. 1169-71 (1980)]. Use of soluble phosphorylated glucan in combination with such agents permits a lower dosage of the toxic antimicrobial agents while still achieving therapeutic effectiveness.

5.5. ROUTES AND METHODS OF ADMINISTRATION

The soluble phosphorylated glucans of the present invention can be administered for prophylatic and therapeutic applications by a number of routes, including but not limited to: orally, by injection including but not limited to intradermally, intraveneously, intraperitoneally, subcutaneously, intramuscularly, etc., topically as a dry powder or in a suitable physiologic carrier, by topical application to nasal and nasopharyngeal linings, and by inhalation via aerosolization and application to respiratory tract linings, etc.

When administered to an animal or a human, the soluble phosphorylated glucan may be combined with water, an aqueous solution or any physiologically acceptable pharmaceutical carrier or vehicle. Moreover as described above, the soluble phosphorylated glucan may be administered in combination with an antimicrobial agent. When a combination of soluble phosphorylated glucan and an antimicrobial agent is desired, each agent may be simultaneously administered, or soluble phosphorylated glucan may be combined with one or more antimicrobial agents and administered as a single composition. The combination may be administered for prophylactic and therapeutic applications by a number of routes, including but not limited to: orally, by injection including but not limited to intraveneously, intraperitoneally, subcutaneously, intramuscularly, intradermally, etc., topically as a dry powder or in a suitable physiologic carrier, by topical application to nasal and nasopharyngeal linings, and by inhalation via aerosolization and application to respiratory tract linings, etc.

According to other embodiments of the present invention, the soluble phosphorylated glucan either alone or in combination with an antimicrobial agent may be administered by a number of delivery modalities including but not limited to the following: incorporated into liposome vesicles; in combination with an albumin complex to increase the intravascular half-life, in combination with a targeting agent such as a polyclonal or monoclonal antibody against a specific infection induced by agents such as a virus, bacterium, fungus or protozoal parasite, etc.; in combination with an anhydrous lipid base for topical or parental administration, etc. In addition, the soluble phosphorylated glucan, either alone or in combination with a known antimicrobial agent can be impregnated on bandages, sutures or dressings either as a dry powder or in a suitable physiologic carrier.

The following series of Examples ae presented for purposes of illustration and not by way of limitation on the scope of the invention.

6. PREPARATION OF SOLUBLE PHOSPHORYLATED GLUCANS 6.1. PREPARATlON FROM PARTICULATE GLUCAN OBTAINED FROM SACCHAROMYCES

Particulate glucan was prepared from Saccharomyces cerevisiae according to the method of Di Luzio et al. (1979, Int'l J. Cancer 24: 773-779). Briefly, using a 6 1 flask, 540 gm of dry yeast (Universal Foods Corp., Milwaukee, Wis.) was suspended in 3 l of 3% aqueous sodium hydroxide solution. The suspension was placed in boiling water bath 4 hours, cooled overnight and the supernatant decanted. This procedure was repeated three times. The residue was then acidified with 800 ml of concentrated hydrochloric acid plus 2 l of 3% hydrochloric acid and placed in a boiling water bath for 4 hours. The suspension was allowed to stand overnight and the supernatant decanted. The residue was further digested with 3 l of 3% hydrochloric acid at 100° C. for 4 hours, cooled overnight and decanted. The 3% hydrochloric acid digestion was repeated twice. The residue was then washed three times with distilled water (20° C.) and twice with distilled water at 100° C. One l of ethyl alcohol was added to the residue, mixed thoroughly and allowed to stand a minimum of 24 hours for maximum extraction. The dark reddish-brown alcohol supernatant was aspirated from the residue and discarded. The alcohol extraction procedure was repeated until the alcohol supernatant was essentially colorless. The alcohol was removed by washing the residue four times with hot water; the particulate glucan preparation was then collected by centrifugation, frozen and lyophilized.

Soluble phosphorylated glucan was prepared according to the method described in Section 5 by solubilization and phosphorylation of the particulate glucan as follows:

18 gm of urea (8M) was dissolved in a flask containing 50 ml dimethylsulfoxide (DMSO) with constant stirring. One gm of particulate glucan was added to form a finely divided suspension. The flask Was heated to 100° C. and 10 ml of phosphoric acid (85%) was added slowly dropwise. The mixture was maintained at 100° C. for 3-12 hours by immersion in a boiling water bath. It is preferred to allow the reaction to proceed for about 6 hours.

During the heating process, a precipitate was formed which became visible after about 1 hour and increased in amount thereafter. After about 6 hours, the mixture was cooled and diluted with 200 ml distilled water to resuspend the precipitate. The mixture was then filtered through coarse, medium and fine sintered funnels to remove the precipitate.

The resulting solution was then molecularly sieved in order to remove low molecular weight (MW) fractions including glucose, DMSO and urea.

In one series of experiments, molecular sieving was accomplished by dialysis for 5 days against running distilled water using Spectrapor membrane dialysis tubing (Fisher Scientific Co; Pittsburgh, Pa.). The MW size range of pores of this tubing is about 12,000 daltons. In another series of experiments, molecular sieving was accomplished using a Millipore dialyzer/concentrator (Millipore Corp., Bedford, Mass.) with a 10,000 MW membrane filter. About 70 l of dialyzing solution were used to remove low MW compounds. In either case, tests for the presence of glucose in the final preparation were negative. Moreover, using high performance gas-liquid chromatography, no DMSO was detectable in the final preparation.

Following molecular sieving, the solution containing the phosphorylated soluble glucan was concentrated and lyophilized. This phosphorylated glucan is stable in a lyophilized state for at least 2 years and at least for 15 months in solution maintained at -20° C.

6.2. PREPARATION FROM CORIOLUS VERSICOLOR

Soluble phosphorylated glucan was prepared from a basidiomycete Coriolus versicolor (Fr. Quel.) as follows:

A commercially available polysaccharide-protein preparation termed "Krestin" or "PSK" obtained from Sanyko Corporation, Tokyo, Japan, was used as the starting material for the preparation of soluble phosphorylated glucan from C. versicolor. This commercial preparation of a relatively crude preparation comprising a beta-1,4, beta-1,3, beta-1,6,-glucan-protein complex. The principal chemical structure of the polyglucose is a main chain of glucose units linked by 1-4 glucosidic bonds, having attached branch or side chains of glucose units linked by beta-1,3 and beta-1,6 glucosidic bonds. The protein content ranges from 15-38%. (Ehrke et al., 1983, Internat'l J. Immunopharm. 5: 34-42; Yamaura and Azuma, 1982, Adv. Immunopharm. 2: 501-507).

Because the commercially available PSK preparation is relatively crude preparation and has a relatively high protein content, intravenous administration of this material is not possible. It must be administered orally.

The PSK polysaccharide-protein complex from C. versicolor was prepared as a soluble phosphorylated glucan (hereinafter "soluble phosphorylated-PSK") as described in Section 5. The isolated soluble phosphorylated-PSK was lyophilized.

6.3. PREPARATION FROM SCLEROTIUM

Soluble phosphorylated glucan was prepared from Sclerotium glucanium as follows:

A commercially available sclero-glucan termed "Polytran R" obtained from Jetco Chemicals, Inc. (Corsicana, Tex.) was used as the starting material. This commercial preparation is a monionic polyglucose of greater than 500,000 daltons MW comprising a linear chain of glucose units linked by beta 1-3 glucosidic bonds in which about 30-35% of the linear chains have appended a single glucose unit linked via a beta 1-6 linkage. When mixed with water or an aqueous solution, Polytran R forms a colloidal suspension that becomes increasingly viscous over a 24 hour period. Because of the formation of such viscous gel, Polytran R is not useful for intravenous administration. A novel, rapid process was used to obtain a colloidal glucan from the sclero-glucan as follows:

One hundred forty grams Polytran R was added to 2.0 liters of 1M NaOH, pH about 14 with constant stirring on a hot plate. The mixture was maintained at room temperature for 4 days. Then the mixture was heated to about 85° C. for about 20 minutes, during which time a dark brown color developed in the mixture. After the mixture was cooled to room temperature, it was filtered through coarse and then medium sintered glass funnels. The filtrate was then passed serially through a series of Millipore filters: 3.0, 1.2, 0.8 and 0.65 microns. The resulting clear filtrate had a dark amber color. An aliquot (500 ml) was diluted to 6.0 liters in a dialzing flask and dialyzed against 40 liters of ultrapure water. The pH of the final concentrated mixture was about 6.7. The colloidal glucan isolated, a light brown spongy material, was lyophilized.

Soluble phosphorylated glucan was prepared from the colloidal glucan as described in Section 5.

In practice, 72 gm of urea (6M) was dissolved in a flask containing 200 ml DMSO with constant stirring. Four gm of colloidal glucan was added to form a finely divided suspension. The flask was heated to 100° C. and 40 ml of phosphoric acid (85%) was added slowly drop wise. The mixture was maintained at 100° C. for 6.0 hours.

During the heating process, a precipitate was formed which became visible and quite noticeable after about 3 hours and increased in amount thereafter. After about 6 hours, the mixture was cooled, and diluted with 4 liters distilled water to resuspend the precipitate. The mixture was then filtered through a 3.0 micron filter.

The resulting solution was molecularly sieved in order to remove low molecular weight fractions. In one series of experiments molecular sieving was accomplished by dialysis (1 liter: 5 liters water).

Following molecular sieving, the solution containing the soluble phosphorylate glucan was concentrated and lyophilized to yield about 4 gms soluble phosphorylated glucan.

7. IMMUNOBIOLOGICAL PROPERTIES OF SOLUBLE PHOSPHORYLATED GLUCANS

In all experiments reported below, animals were maintained on Purina Laboratory Chow ad libitum in air-conditioned rooms maintained on 12 hour light/dark cycles.

7.1. MODIFICATION OF ENHANCED SUSCEPTIBILITY TO OPPORTUNISTIC INFECTIONS IN IMMUNOSUPPRESSED ANIMALS

Animals which are immunosuppressed either because of chemotherapy, congenital or acquired immunodeficiency (e.g., acquired immunodeficiency syndrome or AIDS) are susceptible to infection by a variety of opportunistic organisms. For example, a major cause of death in patients suffering AIDS is pneumonia caused by Penumocystis carinii (see e.g., Jaffee et al., 1983, J. Infect. Dis. 148:339-345; Gottlieb et al., 1981, New Eng. J. Med. 305:1425-1431).

Previous studies by Walzer et al. (1983, J. Reticuloendothel. Soc. 33:1-9; 1979; Infec. Immunol. 24:939-947) have demonstrated that when immunosuppressed by chronic administration of a corticosteroid, the C3H/HeJ strain of mice is more susceptible to pneumonia induced by P. carinii than are other mouse strains. In these animals, like man, development of Pneumocystis pneumonia represents activation of latent infection due to the development of immunosuppression.

The following experiments demonstrate that administration of soluble phosphorylated glucan to chronically immunosuppressed C3H/HeJ mice significantly enhanced survival and reduced susceptibility of these animals to opportunistic infections.

7.1.1. ENHANCED SURVIVAL

In one series of experiments, 100 C3H/HeJ mice (Jackson Laboratories, Bar Harbor, Me.) were divided into 4 groups of 25 mice each. Group 1 received 0.5 ml of a 5% glucose solution intravenously; Group 2, 5 mg soluble phosphorylated glucan intravenously; Group 3, 1.5 mg cortisone acetate (Upjohn, Kalamazoo, Mich.) subcutaneously; and Group 4, both 5 mg soluble phosphorylated glucan intravenously and 1.5 mg cortisone acetate subcutaneously. All mice were treated twice weekly for 5 weeks, and survival was monitored for 60 days. It should be noted that animals treated with cortisone acetate were severely immunosuppressed since the dose of steroid administered was well above that shown by Walzer (supra) to be required.

Results are illustrated in FIG. 3. As demonstrated in FIG. 3, there was no mortality in mice treated either solely with glucose (Group 1) or soluble phosphorylated glucan (Group 2). By day 24, survival of mice treated with corticosteroid alone was 12% (Group 3). Histopathological studies indicated that contributing causes of death were bacterial and fungal infections, including those of the brain. In contrast, by day 24, survival in mice treated with corticosteroid and soluble phosphorylated glucan was about 68% (Group 4). Long term survival of such mice was 66%, highly statisically significant when compared to corticosteroid-treated mice (p<0.001).

7.1.2. ENHANCED RESISTANCE IMMUNO-SUPPRESSED MICE TO ESCHERICHIA COLI INFECTION

The following experiment demonstrates that administration of soluble phosphorylated glucan enhanced resistance of both normal and chronically immunosuppressed mice to infection by E. coli.

Sixty C3H/HeJ mice were divided into 4 groups of 15 mice each. Group 1 received three injections of 5% glucose (0.5 ml) intravenously; Group 2, three injections of 4 mg/animal soluble phosphorylated glucan intravenously; Group 3, three injections of 1.5 mg/animal cortisone acetate subcutaneously; and Group 4, three injections of a combined 4 mg/animal soluble phosphorylated glucan intravenously and 1.5 mg/animal cortisone acetate subcutaneously at three day intervals. Three days following the last injection, the mice received 2.5×10⁷ E. coli bacteria intraperitoneally. Survival was monitored for 15 days post-infection with E. coli.

Results illustrated in FIG. 4 demonstrate 65% survival in normal glucose-treated mice infected with E. coli (Group 1). No deaths occurred in this group after 7 days post-infection with E. coli. In contrast, 0% mortality was observed in normal mice treated with soluble phosphorylated glucan (Group 2). Thus, pretreatment with soluble phosphorlylated glucan significantly enhanced resistance to E. coli infection in normal animals.

Results presented in FIG. 4 also demonstrate marked mortality of mice chronically immunosuppressed by administration of corticosteroid. In immunosuppressed mice treated with glucose (Group 3), 50% mortality was noted at 40 hours and 75% mortality, at 5 days. In marked contrast, in immunosuppressed mice treated with soluble phosphorylated glucan (Group 4) 0% mortality was observed. Thus in both control and cortisone-treated mice, soluble glucan was able to enhance host resistance resulting in complete protection to a gram-negative infection both in normal and cortisone-immunosuppressed mice.

These studies, demonstrate that the administration of soluble glucan to mice receiving immunosuppressive doses of cortisone results in modification of the cortisone-induced susceptibility to infection. Therefore, glucan is capable of modifying not only the immunosuppressive effects of chronic administration of cortisone leading to decreased mortality from spontaneous infections, but also the relatively acute immunosuppressive effects of cortisone.

7.2. MODIFICATION OF BACTERIAL DISEASES IN ANIMALS BY IN VIVO ADMINISTRATION OF SOLUBLE PHOSPHORYLATED GLUCAN 7.2.1. MODIFICATION OF STAPHYLOCOCCUS AUREUS INDUCED SEPSIS

The following experiment demonstrates the effectiveness of in vivo administration of soluble phosphorylated glucan in modifying the lethal effects of sepsis associated with Staphylococcus aureus.

Twenty ICR/TEX mice were divided into two groups and treated as follows. At 3, 2 and days prior to the induction of sepsis, Group 1 received intravenous injections of soluble phosphorylated glucan at 200 mg/kg; Group 2, designated a control group, received intravenous injections of an equivalent volume of isotonic glucose. One day following the third administration of polysaccharide, both groups received an intravenous injection of 1.0×10⁹ cells S. aureus. Survival of experimental and control mice was monitored for 130 days.

Results are illustrated in FIG. 5. As demonstrated therein, at 2 days post-infection with S. aureus, 60% mortality was observed in the glucose-treated mice (Group 2). At the same time, however, 0% mortality was observed in those animals treated with soluble phosphorylated glucan prior to infection. At 8 days post-infection, 27% of the control group survived. In contrast, survival of the animals treated with soluble phosphorylated glucan was 100% at the same time. No further deaths occurred in either groups in 130 days. Thus, pre-treatment with soluble phosphorylated glucan significantly reduced lethality of a subsequent S. aureus infection.

7.2.2. MODIFICATION OF Escherichia coli INDUCED PERITONITIS 7.2 2.1. TIME REQUIRED FOR PROTECTIVE EFFECT

The following experiments demonstrate the effectiveness of intraperitoneal administration of soluble phosphorylated glucan against a subsequent experimentally induced E. coli sepsis.

Seventy nine adult white mice were divided into 8 groups of 8-13 animals each. Group 1, designated control, received 1 ml glucose (5%); Group 2, designated positive control, 3 mg particulate glucan; and Group 3, 12.5 mg soluble phosphorylated glucan at 24 hours prior to challenge with E. coli. Groups 4, 5, 6 and 7 received 12.5 mg soluble phosphorylated glucan at respectively 6, 2, 1, 0 hours prior to challenge with E. coli. Group 8 received 12.5 mg soluble phosphorylated glucan at 2 and 4 hours following challenge with E. coli. All treatments were administered via intraperitoneal injections. E. coli (1.0×10⁸ cells) was also injected via an intraperitoneal route. Results are illustrated in Table 6.

                  TABLE 6                                                          ______________________________________                                         EFFECT OF TIMING OF ADMINISTRATION OF SOLUBLE                                  PHOSPHORYLATED GLUCAN ON MORTALITY DUE TO                                      E. COLI SEPSIS                                                                                           % Survival                                           Group                     Time (Hours)                                         Number           Time     Post-Infection                                       Treatment.sup.a  (Hours).sup.b                                                                           12     16   24   48.sup.c                            ______________________________________                                         1.  Glucose          -24      40   0    0    0                                 2.  Particulate Glucan                                                                              -24      100  100  88   88                                3.  Soluble Phosphorylated                                                                          -24      80   80   70   70                                    Glucan                                                                     4.  Soluble Phosphorylated                                                                          -6       100  100  100  88                                    Glucan                                                                     5.  Soluble Phosphorylated                                                                          -2       20   20   20   20                                    Glucan                                                                     6.  Soluble Phosphorylated                                                                          -1       20   20   20   20                                    Glucan                                                                     7.  Soluble Phosphorylated                                                                          0        30   0    0    0                                     Glucan                                                                     8.  Soluble Phosphorylated                                                                          +2, +4   80   0    0    0                                     Glucan                                                                     ______________________________________                                          .sup.a Group number refers to treatment protocol explained in text. The        number of animals in each group was 8-13.                                      .sup.b Time at which animals were treated.                                     .sup.c No additional mortality was observed in any group after the 48 hou      period.                                                                  

As demonstrated in Table 6, intraperitoneal administration of soluble phosphorylated glucan significantly enhanced survival of mice with experimentally induce E. coli peritonitis (Groups 3 and 4). As observed, the soluble phosphorylated glucan could effectively be administered as late as 6 hours prior to challenge with E. coli.

Administration of soluble phosphorylated glucan either simultaneously with or subsequent to administration of E. coli was not effective in reversing the lethality of E. coli peritonitis (Groups 7 and 8) due to the fulminant nature of the infection.

7.2.2.2. Dose-Response

Another series of experiments was conducted to determine the effect of administration of various doses of soluble phosphorylated glucan on E. coli induced peritonitis and lethality.

One hundred and six white mice were divided into groups of 9-30 mice each. Groups 1-2, designated controls received isovolumetric glucose. Groups 2-7 received soluble phosphorylated glucan at respectively 1, 1, 2, 4, 8, 10, 20, 120, 200 and 260 mg/kg. All injections were administered intraperitoneally at 24 hours prior to the induction of peritonitis by intraperitoneal administration of E. coli (1×10⁸ cells). Results are illustrated in Table 7.

                  TABLE 7                                                          ______________________________________                                         EFFECT OF DOSE OF SOLUBLE PHOSPHORYLATED                                       GLUCAN ON LETHALITY OF INTRAPERITONEAL OF                                      ADMINISTRATION OF E. COLI.sup.a                                                Group                                                                          Number           Number   Dose      %                                          Treatment        of Mice  (mg/kg)   Survival                                   ______________________________________                                         1.  Glucose          30       --      13                                       2.  Soluble Phosphorylated                                                                          22       1       78                                           Glucan                                                                     3.  Soluble Phosphorylated                                                                          12       2       83                                           Glucan                                                                     4.  Soluble Phosphorylated                                                                          12       4       83                                           Glucan                                                                     5.  Soluble Phosphorylated                                                                          12       8       83                                           Glucan                                                                     6.  Soluble Phosphorylated                                                                          9        10      100                                          Glucan                                                                     7.  Soluble Phosphorylated                                                                          9        20      89                                           Glucan                                                                     ______________________________________                                          .sup.a Single injection of either glucose or soluble phosphorylated gluca      given intraperitoneally 24 hours before challenge with E. coli. Survival       was recorded at 24 hours postchallenge.                                  

As demonstrated in Table 7, all doses of soluble phosphorylated glucan ranging from 1 mg/kg to 20 mg/kg were about equally effective in enhancing survival in animals challenged by intraperitoneal infection with E. coli.

7.2.2.3. EFFECTIVENESS OF SOLUBLE PHOSPHORYLATED GLUCAN

The following experiments further demonstrate the effectiveness of intraperitoneal administration of soluble phosphorylated glucan against a subsequently induced E. coli peritonitis.

In one series of experiments, the effectiveness of soluble phosphorylated-PSK was demonstrated. Forty eight adult white mice were divided into 3 groups of 16 animals each. Group 1 designated control, received 0.5 ml of isotonic saline solution intravenously; Group 2, 5 mg commercially available PSK (Sankyo Corporation, Tokyo, Japan) intravenously; and Group 3, 5 mg soluble phosphorylated-PSK intravenously. All glucans were administered at 24 hours prior to challenge with E. coli. E. coli (1×10⁸ bacteria) was injected via an intraperitoneal route. Results are illustrated in Table 8.

                  TABLE 8                                                          ______________________________________                                         EFFECT OF ADMINISTRATION OF SOLUBLE                                            PHOSPHORYLATED GLUCAN FROM C. VERSICOLOR                                       ON MORTALITY DUE TO E. COLI SEPSIS                                                               % Survival                                                                     Time (Hours)                                                                   Post-Infection                                               Group.sup.a                                                                             Treatment      24        48       72                                  ______________________________________                                         1        Saline.sup.b   6         6        6                                   2        PSK.sup.c      63        25       19                                  3        Soluble Phos-  100       100      100                                          phorylated-PSK.sup.b                                                  ______________________________________                                          .sup.a N = 16 mice/group                                                       .sup.b Single injection of either saline or soluble phosphorylatedPSK (5       mg/mouse) was given intraperitoneally 24 hours before challenge with E.        coli.                                                                          .sup.c Commercially available PSK (Sankyo Corporation, Tokyo, Japan) was       administered intravenously (5 mg/animal) 24 hours before challenge with E      coli.                                                                    

As illustrated in Table 8, both the commercially available PSK and the soluble phosphorylated-PSK glucans demonstrated significant protective activity against E. coli sepsis at 24 hours post-infection (i.e., 63% and 100% survival as compared to 6% in saline control animals Group 1). In marked contrast to the PSK preparation, however, the soluble phosphorylated glucan-PSK prepared according to the present invention showed greatly enhanced effectiveness against infection on a long term basis. At 72 hours post-infection, no mortality was observed in the group treated with soluble phosphorylated-PSK (Group 3). At the same time, 81% mortality was observed in the group treated with PSK (Group 2).

In another series of experiments, the effectiveness of soluble phosphorylated glucan obtained from Sclerotium glucanium was demonstrated.

Forty adult white mice were divided into 4 groups of 10 animals each. Group 1 designated control, received isovolumetric dextrose 5% (w/v); Group 2, 1 mg/mouse particulate glucan; Group 3, 1 mg/mouse soluble phosphorylated glucan from Saccharomyces cerevisiae; and Group 4, 1 mg/mouse SPG-RF, intraperitoneally. All control and glucan treatments were administered 24 hours prior to challenge with E. coli. E. coli (1×10⁸ bacteria) was injected via an intraperitoneal route. Results are illustrated in Table 9.

                  TABLE 9                                                          ______________________________________                                         EFFECT OF GLUCANS ON SURVIVAL OF MICE WITH                                     E. COLI SEPSIS                                                                            % Survival                                                                     Time (Hours) Post-Infection                                         Group.sup.a  14      24      48    72    96                                    ______________________________________                                         1. Control   40%     0       0     0     0                                     2. Particulate                                                                              80%     70%     70%   70%   70%                                   Glucan                                                                         3. Soluble Phosphor-                                                                        100%    90%     90%   80%   80%                                   ylated Glucan.sup.b                                                            4. Soluble Phosphor-                                                                        100%    100%    100%  100%  100%                                  ylated Glucan-RF.sup.c                                                         ______________________________________                                          .sup.a Each group consisted of 10 animals.                                     .sup.b Soluble phosphorylated glucan obtained from Saccharomyces               cerevisiae.                                                                    .sup.c Soluble phosphorylated glucanRF represents soluble phosphorylated       glucan obtained from Scelerotium glucanium.                              

As illustrated in Table 9, all glucan preparations demonstrated significant protective activity against E. coli sepsis at 24 hours post-infection (i.e., respectively 70%, 90%, 100% as compared to 0% in glucose control animals Group 1). The survival rate stabilized at 72 hours post-infection. At that time, the Group 2 treated with particulate glucan showed only 70% survival. In contrast, however, animals treated with soluble phosphorylated glucan, Groups 3 and 4 showed 80% and 100% survival. Thus these preparations clearly are effective against Escherichia coli induced sepsis.

7.3. EFFECT OF SOLUBLE PHOSPHORYLATED GLUCAN ON VIRAL INDUCED HEPATITIS

Previous studies have demonstrated that particulate glucan is capable of increasing survival, inhibiting hepatic necrosis, and maintaining an activiated state of phagocytic activity in mice challenged with murine hepatitis virus (MHV) strain A59 (Williams and Di Luzio, 1980, Science 208:67-69).

The following experiment demonstrates that prior administration of soluble phosphorylated glucan enhanced survival of mice with experimentally induced viral hepatitis.

Twenty male C57BL/6 Tex mice (Timco, Houston, Tex.) were divided into two groups. Group 1 designated controls, received intravenous injection of glucose (0.5 ml/mouse) and Group 2 received intravenous injection of soluble phosphorylated glucan (5 mg/mouse) at 3, 2 and 1 days before induction of acute viral hepatitis. Hepatitis was induced by intraperitoneal injection of 16 complement fixing units (CFU) of MHV strain A59.

Survival of mice was monitored for 30 days following administration of virus. Results are illustrated in FIG. 6.

As demonstrated in FIG. 6, intravenous administration of soluble phosphorylated glucan significantly enhanced survival in mice with acute viral hepatitis. At 6 days post-induction of hepatitis, 50% survival was observed in the control group. In contrast, at that time 100% survival was observed in the group pre-treated with soluble phosphorylated glucan. No further mortality was observed in either group (day 7-30).

7.4. EFFECT OF ORALLY ADMINISTERED SOLUBLE PHOSPHORYLATED GLUCAN ON Candida albicans-INDUCED SEPSIS

The following experiment demonstrates that orally administered soluble phosphorylated glucan is effective in modifying the lethal effects of sepsis induced by the yeast Candida albicans.

Twenty-five male ICR/Tex mice were divided into two groups. Group 1 (13 animals) were maintained for seven days on drinking water containing 5.0 mg/ml soluble phosphorylated glucan. The mice drink about 1.2-1.5 ml/day, thus treated animals received about 7 mg/day soluble phosphorylated glucan orally. Group 2, designated control group (12 animals), were maintained on tap water throughout the experimental period. On day zero, all animals were injected with Candida albicans (3.0×10⁶ cells/mouse) intravenously. Group 1 continued to receive soluble phosphorylated glucan orally, in drinking water, for 5 days post-infection, then these animals were maintained on tap water. The body weight of mice in both groups was monitored. Mice in both groups 1 and 2 gained weight at the same rate. Survival in both groups was also monitored. Results are graphically illustrated in FIG. 7.

As demonstrated in FIG. 7, oral administration of soluble phosphorylated glucan pre-and for 5 days post-infection with C. albicans resulted in a significant, but transient increase in survival of mice. At 25 and 30 days post-infection, the survival in the soluble phosphorylated glucan-treated group was significantly greater (at the p<0.05 level) than in the control group. The median survival time for the control Group was 18 days; whereas for the soluble phosphorylated glucan treated group, median survival time was 30 days. With regard to long-term survival, however, the ultimate outcome was not significantly altered. Thus, this experiment suggests that higher dose of soluble phosphorylated glucan may be needed when administered orally.

7.5. ENHANCEMENT OF MACROPHAGE PHAGOCYTIC ACTIVITY

The following experiment demonstrates that administration of soluble phosphorylated glucan significantly enhanced phagocytic function of macrophages.

Twenty male ICR mice were divided into two groups of 10 each. At 3, 2 and 1 day prior to determiniation of phagocytic activity, Group 1, designated control received injections of isovolumetric saline; Group 2, soluble phosphorylated glucan (200 mg/kg). All injections were administered intravenously.

Phagocytic function was evaluated by measuring the rate of intravascular clearance of colloidal carbon (Cll/143 (a), Gunther Wagner, Hanover, Germany) according to the method of Wooles et al. (1962, Rad. Res. 16: 546-554). Colloidal carbon was administered (640 mg/kg) intraveneously and serial blood samples were obtained from tail veins. Aliquots were hemolyzed in 4.0 ml of 0.5% sodium carbonate and the concentration of colloidal carbon was determined spectrophotometrically. The half-time (t/2) was taken as the time at which the optical density or concentration was one-half the zero time value as determined by extrapolation of the clearance curves to zero time. Results are presented in Table 10.

                  TABLE 10                                                         ______________________________________                                         EFFECT OF SOLUBLE PHOSPHORYLATED GLUCAN ON                                     MACROPHAGE PHAGOCYTIC FUNCTION                                                                                   Intravascular                                                                  Clearance                                               Body Weight                                                                               Liver Weight                                                                               t/2                                          Treatment.sup.a                                                                           (gm)       (gm)        (minutes)                                    ______________________________________                                         Saline     24.8 ± 0.82                                                                            1.94 ± 0.05                                                                             7.6 ± 0.73                                Soluble    25.2 ± 1.03                                                                            1.82 ± 1.03                                                                             3.5 ± 0.58*                               Phosphorylated                                                                 Glucan                                                                         ______________________________________                                          .sup.a N = 10 per group.                                                       *p < 0.001                                                               

As demonstrated in Table 10, administration of soluble phosphorylated glucan significantly enhanced phagocytic function as reflected by a 55% increase in clearance (Table 10). As previously observed, no increase in liver weight occurred (Table 10).

7.6. ENHANCEMENT OF MACROPHAGE SECRETORY ACTIVITY

A major secretory product of macrophages, particularly in an activated state, is a mediator molecule called Interleukin I. Interleukin I is a polypeptide which induces, both in experimental animals and man, an acute phase protein response. This response includes increased erythrocyte sedimentation rates, leukocytosis, elevated acute phase proteins, and development of fever due to endogenous pyrogen. Additionally, Interleukin I has the ability to profoundly stimulate T-cell activation and proliferation. Thus, Interleukin I is a lymphocyte activating factor capable of cellular recruitment and, hence, enhances host defense activity.

The following experiment demonstrates that administration of soluble phosphorylated glucan stimulates macrophage secretory activity as assayed by the secretion of Interleukin I.

A number of rats (16) were injected intravenously with soluble phosphorylated glucan (200 mg/kg). Eight control animals received isovolumetric glucose. Plasma samples were obtained at 1, 3, 5, 8, 24, 48, 72 and 168 hours post-injection.

Production of Interleukin I was evaluated employing C-57 BL/6J thymocytes. Cultures of thymocytes (1×10⁶ cells) were incubated with media alone, or with 0.1 ml plasma from control or soluble phosphorylated glucan-treated rats. The cell cultures were maintained for 24 hours, at which time 1 uCi of ³ H-thymidine was added, and incubation was carried out for another 24 hour period. At that time, thymidine uptake was measured. Results are presented in FIG. 8.

As illustrated in FIG. 8, serum obtained from soluble phosphorylated glucan-treated rats showed increased Interleukin I activity as reflected by the elevation in thymidine uptake by thymocytes at 1, 24, 48 and 72 hours compared to serum obtained from rats treated with glucose. Thus, soluble phosphorylated glucan rapidly activates macrophages and increases secretory activity, as reflected by elevated plasma interleukin levels. The nature of the 24-72 hour peak remains to be established.

8. SYNERGISTIC EFFECT OF SOLUBLE PHOSPHORYLATED GLUCAN AND AN ANTIBIOTIC AGAINST E. coli INDUCED INFECTION

The following experiments demonstrate the synergistic effectiveness of in vivo administration of soluble phosphorylated glucan together with an antimicrobial agent against sepsis induced by E. coli.

Forty eight mice were divided into 4 groups of 12 mice each. Group 1 designated control group received isotonic saline solution; Group 2, 0.02 mg gentamicin intramuscularly; Group 3, 0.1 mg soluble phosphorylated glucan intraperitoneally; and Group 4, a combination of 0.02 mg gentamicin and 0.1 mg soluble phosphorylated glucan.

Animals treated with gentamicin either alone or in combination with soluble phosphorylated glucan received the antimicrobial agent about 2 hours prior to challenge with E. coli. Animals treated with soluble phosphorylated glucan either alone or in combination with gentamicin received the glucan about 24 hours prior to challenge. All groups were challenged by an intraperitoneal injection of a lethal dose of E. coli (1×10⁸ bacteria). Effect of the treatment on survival was monitored. Results are illustrated in Table 11.

                  TABLE 11                                                         ______________________________________                                         EFFECT OF SOLUBLE PHOSPHORYLATED GLUCAN AND                                    GENTAMICIN ON SURVIVAL FOLLOWING                                               SEPSIS INDUCED BY                                                              E. COLI                                                                                           % Survival                                                                     Time (Hours)                                                Treatment          Post-Infection                                              Group No..sup.a  24        48     72                                           ______________________________________                                         1.    Control        18        4    0                                          2.    Soluble Phosphorylated                                                                        36        9    9                                                Glucan                                                                   3.    Gentamicin     14        9    0                                          4.    Soluble Phosphorylated                                                                        83        56*  52*                                              Glucan & Gentamicin                                                      ______________________________________                                          .sup.a N = 12 mice/group. Group number refers to treatment protocol            explained in text.                                                             *p < 0.05.                                                               

As demonstrated in Table 11, the control group showed 82%, 96% and 100% mortality at 24, 48 and 72 hours respectively. Group 2 treated with gentamicin alone showed similar results, indicating that the dose administered was ineffective against the lethal E. coli infection. Group 3 treated with soluble phosphorylated glucan alone showed similar results, also indicating that the dose of glucan was ineffective against the lethal Escherichia coli infection.

In marked contrast, however, Group 4 treated with a combination of soluble phosphorylated glucan and gentamicin showed 83, 56 and 52% survival at 24, 48 and 72 hours respectively. Those animals which were alive at 72 hours, survived indefinitely. Hence these results clearly demonstrate that combined administration of soluble phosphorylated glucan and gentamicin exerted a synergistic effect leading to enhanced long term survival to an LD₁₀₀ dose of E. coli.

In an effort to further evaluate the synergistic effect of the combined treatment, another group of mice were divided into 4 treatment groups. Group 1 designated control received isotonic saline solution; Group 2, 0.02 mg gentamicin intramuscularly; Groups 3, 0.1 mg soluble phosphorylated glucan intraperitoneally; and Group 4, a combination of 0.02 mg gentamicin and 0.1 mg soluble phosphorylated glucan. All groups were challenged by an intraperitoneal injection of a lethal dose of E. coli (1×10⁸ bacteria). Soluble phosphorylated glucan was administered about 24 hours prior to E. coli challenge. Gentamicin was administered about 2 hours prior to challenge with E. coli. The number of E. coli present in the peritoneal cavity of animals from the various treatment groups was determined. Results are presented in Table 12.

                  TABLE 12                                                         ______________________________________                                         INFLUENCE OF SOLUBLE PHOSPHORYLATED                                            GLUCAN AND GENTAMICIN, ALONE OR IN                                             COMBINATION, ON E. COLI IN THE PERITONEAL CAVITY                               Treatment       Concentration E. coli                                          Groups.sup.a    (No. cells/ml of Peritoneal Fluid)                             ______________________________________                                         1   Control         483 × 10.sup.5                                       2.  Gentamicin      12 × 10.sup.5                                        3.  Soluble Phosphorylated                                                                         3 × 10.sup.5                                             Glucan                                                                     4.  Soluble Phosphorylated                                                                         1 × 10.sup.5                                             glucan + Gentamicin                                                        ______________________________________                                          .sup.a N = 8-14 mice/group.                                              

The concentration of viable E. coli in peritoneal fluid of control mice was 483×10⁵ /ml at 8 hours post-challenge (Group 1). This number is 41 fold greater than that observed in the gentamicin-treated group which was about 12×10⁵ /ml (Group 2). Soluble phosphorylated glucan-treated mice showed at 99.4% reduction in E. coli when compared to the saline group, indicating a marked effect of glucan alone.

When glucan and gentamicin treatments were combined, the antibacterial effect was most pronounced. The number of bacteria in the combined therapy group was reduced by 99.8% when compared to the control, 92% when compared to the gentamicin-treated animals and 66% when compared to the glucan treatment alone, respectively.

These studies, coupled with survival data, demonstrate the advantages of combined therapy. It is clearly possible to enhance the effectiveness of antibiotics by administering glucan. This will allow employment of lower doses of antibiotics which may reduce toxicity.

The invention described and claimed herein is not to be limited in scope by the specific embodiments herein disclosed, since these embodiments are intended as illustrations of several aspects of the invention. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. 

What is claimed is:
 1. A method for treatment of an infection caused by a parasite in animals or humans, comprising: administering to an animal or a human affected with said infection, a therapeutically effective amount of a soluble glucan which comprises a phosphorylated poly-[beta-(1-3)glucopyranose] chain which is characterized by:(a) the capability of dissolving in water or an aqueous solution; (b) being non-toxic, non-immunogenic and substantially non-pyrogenic; and (c) the capability of exerting a pronounced immunobiological response when administered in vivo to an animal or to a human.
 2. The method according to claim 1, in which the soluble glucan is further characterized by the substantially complete absence of triple helical chains as determined by nuclear magnetic resonance spectroscopy.
 3. The method according to claim 1, in which the soluble glucan is further characterized by having a degree of phosphorylation ranging from about 1.4% to about 3.4%.
 4. The method according to claim 1, in which the soluble glucan is further characterized by having a molecular weight ranging from about 10,000 to about 100,000 daltons.
 5. The method according to claim 1, in which the soluble glucan is further characterized by having a molecular weight ranging from about 100,000 to about 500,000 daltons.
 6. The method according to claim 1, in which the parasite comprises Leishmania donovani or Schistosoma mansoni.
 7. A method for the prevention of an infection caused by a parasite in animals or humans, comprising: administering to such an animal or a human a prophylactically effective amount of soluble glucan which comprises a phosphorylated poly-[beta-(1-3)glycopyranose] chain which is characterized by:(a) the capability of dissolving in water or an aqueous solution; (b) being non-toxic, non-immunogenic and substantially non-pyrogenic; and (c) the capability of exerting a pronounced immunobiological response when administered in vivo to an animal or to a human.
 8. The method according to claim 7, in which the soluble glucan is further characterized by the substantially complete absence of triple helical chains as determined by nuclear magnetic resonance spectroscopy.
 9. The method according to claim 7, in which the soluble glucan is further characterized by having a degree of phosphorylation ranging from about 1.4% to about 3.4%.
 10. The method according to claim 7, in which the soluble glucan is further characterized by having a molecular weight ranging from about 10,000 to about 100,000 daltons.
 11. The method according to claim 7, in which the soluble glucan is further characterized by having a molecular weight ranging from about 100,000 to about 500,000 daltons.
 12. The method according to claim 7, in which the parasite comprises Leishmania donovania or Schistosoma mansoni.
 13. The method according to claim 1, in which the glucan is administered intradermally, intravenously, intraperitoneally, subcutaneously, orally, topically, or by inhalation.
 14. The method according to claim 7, in which the glucan is administered intradermally, intravenously, intraperitoneally, subcutaneously, orally, topically, or by inhalation.
 15. A method for treatment of an infection caused by a parasite in animals or humans, comprising: administering to an animal or a human affected with said infection a therapeutically effective amount of composition which comprises a phosphorylated poly-[beta-(1-3)glucopyranose] chain which is characterized by:(a) the capability of dissolving in water of an aqueous solution; (b) being non-toxic, non-immunogenic and substantially non-pyrogenic; and (c) the capability of exerting a pronounced immunobiological response when administered in vivo to an animal or to a human, in combination with an antimicrobial agent effective against the infection.
 16. The method according to claim 15, in which the composition is administered intradermally, intravenously, intraperitoneally, subcutaneously, orally, topically, or by inhalation. 